Conclusive evidence for ‘Selfish Gene’ theory found.
June 25, 2008 on 7:05 pm | In fauna, science | 5 CommentsI have to admit, I never really got evolution in any sophisticated way before I read Richard Dawkins‘ seminal 1976 book, The Selfish Gene. Dawkins illustrated the foundation of a paradigm shift in evolutionary biology away from group selection or kin selection and toward the gene as the unit of selection driving evolution. That shift shaped the whole of modern biology, and selfish gene theory is the predominant model used by scientists today, with notable exceptions such as E. O. Wilson. Before I read The Selfish Gene, I knew that evolution by natural selection made accurate predictions about the observable biological world, but the nuances of its mechanism—gene selection—were over my head. It wasn’t elegantly taught in my high school biology classes, if it was even taught at all. I recall it being discussed in more depth in my undergrad life sciences courses at the University of Maryland, but that was, unfortunately, around the time I was tuning out (temporarily) academic ambition. It was after reading Dawkins’ The God Delusion that I was so impressed with his writing tone and style I purchased The Selfish Gene. And science, am I ever glad I did. Each chapter seemed to evoke another Eureka! moment, where the dense veil of complexity was lifted from life and I felt a renewed calling toward the study of biology (my first declared major in college).
That said, you can understand why I am so excited about this: next month, the journal Genetics will publish research findings by University of Western Ontario biologist Graham Thompson, and Peter Oxley and Benjamin Oldroyd of the University of Sydney in Australia, who managed to isolate part of the honeybee genome that is responsible for reproductive altruism.¹ (Full text of the article is available now).² As you may know, female worker honeybees [order Hymenoptera] are sterile. In a honeybee colony, the queen is the only reproductively active female. Sex determination for honeybees is haplodiploid, meaning that the queen may lay fertilized female eggs (with two sets of chromosomes, or diploid), or unfertilized male eggs (with one set of chromosomes, or haploid). The queen, having stored sperm in a spermatheca during her numerous mating flights (what a slut!), can choose how many male and female offspring to produce. Although all her female offspring possess the genetic potential to be queens, the overwhelming majority of them will remain sterile workers, toiling away to feed and groom the queen as she becomes a huge sibling factory. Their ovaries will remain inactive, and they will devote their lives to the queen. Occasionally, ‘anarchist’ colonies of honeybees are found, in which a small proportion of females besides the queen activate their ovaries and begin to reproduce. Thompson, Oxley, and Oldroyd have at last discovered what appears to be conclusive, material evidence that the selfish gene is real! Specifically, what they have done is identified four quantitative trait loci (QTLs) that account for 25% of the phenotypic variance in ovary activation. These are regions of the honeybee genome that are almost certain to contain genes responsible for the selfish ‘cheating’ behavior found in the ‘anarchist’ colonies. Although this does not mean that the actual genes have been defined, it does mean that they are now very close to doing so. So the theoretical assumption underpinning modern biology, although quite strong on its own, finally has physical, molecular evidence to support it. This sort of thing makes me a bit weak in the knees, so please forgive my ebullience.
Oh, and in case you couldn’t tell, I <3 honeybees.
¹ Western News – The University of Western Ontario
² Genetics Volume 179, No. 3, July 2008. Four quantitative trait loci that influence worker sterility in the honeybee (Apis mellifera), by Peter R. Oxley, Graham J. Thompson, and Benjamin P. Oldroyd.
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No matter how significant this discovery turns out to be, it will not confirm the basis of The Selfish Gene. The evidence Dawkins gives fails to meet the standards of the scientific method, or of Popper’s standards of testability and falsifiability. His “survival machine” is no more than an opinion.
Comment by Steve Davis — July 6, 2008 #
Steve, that’s kind of like when people argue that Darwin was not justified in proposing the theory of evolution by natural selection because he didn’t know about DNA or Mendelian genetics. Your dig at the selfish gene here falls pretty well short of moving me. If not for selfish genes, how do you explain kin altruism or reproductive altruism (as I discussed in this post)? Dawkins himself presented very compelling evidence, but that does not need to stand on its own. Thousands of papers on biology and other evolution-related topics have cited Dawkins as a leading expert and incorporated the gene’s eye view of natural selection into their theoretical frameworks. Dawkins put biological science on high throttle, and look at what’s happened to it in the last three decades! You can say you don’t like the survival machine metaphor if you like, but you’re dead wrong on the testability and falsifiability thing.
Comment by simian — July 11, 2008 #
Hi Simian, sorry I’ve taken so long to reply.
Don’t get me wrong, I see no problem with investigating selfish gene theory, it’s Dawkins presentation of it that worries me.
Non-scientific theorising has been defined as follows, (from Wikipedia I think) untestable claims, reliance on confirmation rather than refutation, lack of openness to testing, personalisation of issues and the use of misleading language. The only one to which he can claim “not guilty” would be lack of openess to testing as far as I know. His survival machine is untestable, he relies heavily on confirmation when for every example of selfishness an example of unselfishness can be found, he personalises debate as in his recent unprofessional treatment of Freeman Dyson, and his “selfish gene” is deliberately misleading despite his protests to the contrary. He claims that he uses the word in a technical sense but a careful reading of the book shows this is not the case.
Dawkins did put science on high throttle as you suggest, but was that in reverse? A whole generation of biologists has grown up thinking that selfish gene theory as presented by Dawkins is serious science, even scientific orthodoxy, when in fact numerous scientists of greater repute and achievement than Dawkins do not accept his work. His success is due to his popularisation of biology, his journalistic skills, not for the fact that he advanced human knowledge. His work on memes is far more substantial, and will endure I believe, but this is more in the field of sociology rather than science. Thanks for taking the time to discuss the matter. Steve
Comment by Steve Davis — July 19, 2008 #
Dear Steve Davis,
I find Dawkins argument very compelling. You need consider the points in the argument rather than see what others think. It says that the only replicators are the genes; that the unit of selection is also gene because all other entities, individuals, groups are ephermeral. These are simple facts and you cannot escape them. The rest of his Dawkins’s work is the articulation of the implication of these simple facts. I write this to see you response.
Simian please let me know when Steve answers, and thanks.
Comment by Shwan — November 1, 2008 #
Hello there Shwan, thanks for your input.
I believe that the unit of selection cannot be the gene for a very simple fact that Dawkins has overlooked, individual genes are not selected, it is the group of genes, the organism, that is selected. Take the example of a characteristic for speed in a predator. No matter how fast a predator might be, it will not survive if other characteristics impair its ability to hunt.
Likewise with its ability to reproduce. it will not pass on its favourable characteristics if it has other characteristics that make it offensive to potential mates or that prevent it mating.
Clearly it is the total package that is selected, not an individual gene. This was recognised by Wilson and Wilson in their recent paper titled “Rethinking the Foundation of Sociobiology”.
The implications of this are quite profound. If it is groups of genes that are selected, then all natural selection is group selection.
Comment by Steve Davis — December 8, 2008 #